1. Field of the Invention
The invention relates to a method for polishing stainless steel press plates used in the manufacture of decorative laminates. More particularly, the invention relates to the manufacture of nondirectional stainless steel press plates and the decorative laminates made using the fabricated nondirectional steel press plates.
2. Description of the Prior Art
Stainless steel press plates are commonly used in the manufacture of decorative laminates. The steel press plates sandwich a pair of decorative laminate stacks with the decorative surfaces facing the steel press plates. In this way, the steel press plates impart a desired texture and gloss to the decorative laminates as they are pressed in a conventional manner.
Where it is desired to impart a rough texture to a decorative laminate, the surface of the steel press plate is roughed up, for example, by shot peening the steel press plate prior to use in the fabrication of the decorative laminate. Where a high gloss decorative laminate is desired, the steel press plate is polished until it resembles a mirror.
While various techniques are known for polishing steel press plates in this way, most techniques fail to produce a nondirectional finish on the steel press plate. That is, the resulting polished steel press plate includes distinct lines running in the polishing direction. These lines are clearly noticeable to those skilled in the art and negatively effect the finish of the steel press plates. The lines ultimately effect the final appearance of decorative laminates manufactured using the polished steel press plates.
Specifically, the distinct lines vary the gloss appearance of the steel press plate as the polished steel press plate is viewed from various angles. As with the polished steel press plates, decorative laminates manufactured using the directional polished press plates exhibit distinct and different gloss characteristics when view from various angles. This is undesirable.
Various techniques are known for producing nondirectional press plates. However, these techniques are highly involved and require the use of physically and environmentally hazardous chemicals to achieve desired results. For example, steel press plates are first spindle ground using 80, 100, 120, 150, 180, 200 and 280 grit sanding paper in various combinations depending upon the condition of the press plate at the beginning of the polishing process. The plate is then prepolished with Ursula Rath GmbH red (2015) and blue (3208) polishing pastes. The plate is polished for 45 minutes at approximately 50 AMP pressure with each of the pastes. During the course of this treatment, the plate is treated three times with the red paste and three times with the blue paste. The edges of the plate are then treated to remove any imperfections and the plate is cleaned with a degreasing powder.
Pure beef fat and green paste (Unipol 239) are then alternately applied for 35-40 minutes at approximately 15 AMPS. Final polishing is completed with a compound call "Langsol". Langsol should never be applied directly on the plate, but is put on the machine table and absorbed with the buffers. The Langsol is then used to polish the plate while hardly touching the surface of the plate (15 AMP pressure). The plate is then treated again with a degreasing powder to remove any grease left over from the treating compounds.
While the process described above does produce a desirable nondirectional steel press plate, the process requires many steps and is highly time consuming. More importantly, the treatment process uses a variety of highly caustic polishing compounds. The disposal of these compounds is highly regulated, and there is a movement to ban the use of such compounds in industrial processing.
As a result, a need exists for a polishing technique to produce nondirectional steel press plates used in the manufacture of decorative laminates. The technique must be relatively simple and eliminate the need for hazardous polishing compounds. The present invention provides such a technique, as well as steel press plates and the decorative laminates produced in accordance with the present technique.